Rendering Tilt Brush FBX?
I have been facing the same issues and so far I have figured out the following.


Change the default vertex color name from 'color' to something else (I used 'col1'). “color” named vertex color layers are not working for some reason.
Create an Attribute node in the node graph
Use the vertex color name that you used in step 1
Connect the Attribute.color to BSDF.Base Color




For the textures, the following setup seems to be working


Select the tilt brush stroke mesh
Set the material blend mode to Alpha Clip
Add an Attribute node and choose the vertex color channel 
We will use the Texture node's alpha
Use the alpha as a multiplier with a custom value
Create an emission node


I am still working on making the texture workflow better, hope this helps.



UPDATE

Using a Transparent BSDF and a mix shader better results can be obtained. Following is an example using Cycles. With Cycles there are no Blend mode options (as specified in the original answer. Blend modes are EEVEE specific)